The Astrolium natal chart is a working chart, not a souvenir. It runs the Swiss Ephemeris core that Solar Fire and Astro Gold use, with 23 house systems, 20,000 named asteroids, the Robson and Brady fixed star catalogs, and Arabic parts all on the wheel. Drag any layer on or off and the wheel re-renders in under 300 ms.
The free chart generator casts a natal without signup. The how-to-read-a-natal-chart guide walks through the reading order. For the timing layer that attaches to any natal, see predictive timing. For the partnership view, see synastry. For the $29 per month Pro plan, see pricing.
What a working natal chart needs
Most natal-chart tools optimize for the first reading. The astrologer's problem is the hundredth. You need a chart that opens in 1 click, re-renders the moment you swap a house system, and saves to the client's profile so the next session picks up where the last one stopped. Speed and continuity, not novelty.
Astrolium was built for that second problem first. The wheel renders in under 300 ms even with asteroids, fixed stars, and Arabic parts all turned on. The Swiss Ephemeris core matches Solar Fire to the arc second, so positions are not a source of doubt. And every chart you cast in Pro lands in a client profile alongside session notes, intake forms, and the rest of the history.
The four layers
The wheel itself
The Astrolium wheel ships in two layouts: classical (Hellenistic order, traditional rulers, planets grouped by sect) and modern (Pluto, Uranus, Neptune as primary rulers, modern aspect orbs). Toggle between them from any reading view. Aspect lines render with weight by orb, not by hard count, so a tight Venus-Mars conjunction at 1 degree visually dominates a loose Venus-Mars at 7 degrees.
The house system dropdown covers 23 options: Whole Sign (default), Placidus, Koch, Porphyry, Equal, Regiomontanus, Campanus, Alcabitius, Morinus, Topocentric, Meridian, Krusinski, APC, Carter Poli-Equatorial, Sripati, and 8 more. Pick once per project or set a global default. The wheel re-renders without re-entering birth data.
Asteroids and minor bodies
The Astrolium asteroid layer covers the full Minor Planet Center named catalog: 20,000 named bodies, queryable by name or number. The classical four (Ceres, Pallas, Juno, Vesta), Chiron, Lilith (both Black Moon and the asteroid), the Centaurs (Pholus, Nessus, Chariklo), and the trans-Neptunian objects (Sedna, Eris, Haumea, Makemake) are on by default. Everything else lives in the search box.
Add an asteroid to the wheel and it stays there until you remove it. Most practitioners build a 3 to 5 asteroid set they re-use across clients. Astrolium lets you save that set as a preset so a new chart opens with your asteroids already laid on.
Fixed stars
The Robson 49-star list (the traditional set, Vivian Robson 1923) is on by default. Brady's 115-star list is 1 click away from any chart. Parans (stars that rise, culminate, set, or anti-culminate with a planet) are computed by latitude and shown as a small badge next to the planet they paran with. Risings and culminations within 1 degree of an angle are flagged on the wheel itself.
Arabic parts
The Astrolium parts layer covers the 7 Hermetic Lots used in Hellenistic predictive (Spirit and Fortune are the two that drive Zodiacal Releasing), the Bonatti list of 97 parts, and a custom-formula entry for anything that is not on either list. Each part renders on the wheel as a small glyph with the formula on hover.
What this replaces
A working practitioner today usually runs 3 tools to get the same coverage Astrolium ships in 1 tab.
- Solar Fire for the wheel itself and the house systems. Strong reference. Windows only, paid asteroid add-on, no client memory.
- Astrodienst or a free web calculator for asteroid quick-checks. Free, but the chart re-casts from scratch on every click, and there is no save target.
- A spreadsheet or Notion page for the client history that connects this chart to the last reading. Free, but disconnected from the chart itself.
Astrolium folds the three into 1 tab. The wheel and the layers live with the client. The next time you open that client, the chart is the one you left, with the asteroids and fixed stars you toggled on last time.
How accuracy works
Both Solar Fire and Astrolium use the Swiss Ephemeris, a re-implementation of NASA JPL's DE431 ephemeris that is accurate to better than 1 arc second for the range 13201 BC to AD 17191. Planetary longitudes, declinations, and right ascensions match between the two programs to a precision orders of magnitude tighter than any wheel can render visually.
What can differ between programs is configuration, not math. Astrolium ships the Hand/Schmidt bound table by default (the table modern Hellenistic scholarship has settled on), while Solar Fire ships the older Egyptian table. You can swap to Egyptian or Ptolemaic in 1 click. Asteroid spellings are normalized to the Minor Planet Center canonical list, so "Juno" and "3 Juno" resolve to the same body.
The natal calculation itself is deterministic: same birth data plus same configuration produces the same chart, every time, on every platform.
Working with the chart day to day
The natal chart is the door to every other technique in Astrolium. From the wheel you can:
- Open the predictive timing ribbon with profections, Zodiacal Releasing, and transits stacked on one scrubbable timeline.
- Run synastry against any other chart in your roster in 2 clicks. The 5x7 inter-aspect grid renders in 80 ms.
- Cast progressions, solar returns, lunar returns, or a Davison composite from the same data record without re-entering anything.
- Generate a 1 page PDF interpretation from the AI assistant, in any of 9 languages, with citations to the natal positions it is reading from.
The chart is also the unit of save: every chart you cast in Pro lands in the client profile, attached to session notes and the rest of the history. The CRM module is what turns Astrolium from a calculator into a workspace.
Pricing
The natal chart itself is free. Cast as many as you want from the free chart generator with no signup. The save-to-client-profile, AI interpretation, and predictive ribbon layers are part of the $29 per month Pro plan, with a founding-member rate of $14.50 per month for life. See pricing for the full breakdown.
Continue exploring
- Chart generator — the free natal calculator
- How to read a natal chart — the reading method
- Predictive timing — the live scrubber for profections, ZR, and transits
- Synastry — two charts, one reading
- Solar Fire vs Astrolium — the desktop comparison